The full monsoon is set to begin on Friday, the 20th, bringing heavy rain accompanied by strong winds and thunder to most areas nationwide.

On the 16th morning, as heavy rain pours down on Daegu's Susung-gu, citizens open umbrellas to avoid the rain while crossing the street. /Courtesy of News1

According to the Korea Meteorological Administration on the 19th, rain is expected to begin on the 20th in the central region, Jeolla Province, and Jeju Island, expanding to North and South Gyeongsang provinces from the morning to midday.

The metropolitan area is forecasted to receive heavy rain of 30 to 50 mm per hour from the afternoon to night. Some areas, including northern Gyeonggi Province, central and northern Gangwon inland, and southern Chungcheong Province, could see over 150 mm of rain. Thunder and lightning, along with strong winds, are also expected across the country.

Rain is expected to fall across most parts of the country until Saturday, the 21st.

The expected rainfall until the 21st is ▲Seoul, Incheon, Gyeonggi Province, and the five islands of the western sea 50 to 100 mm ▲Central and mountainous Gangwon 50 to 100 mm ▲Eastern Gangwon 10 to 50 mm ▲Daejeon, Sejong, Chungnam, and Chungbuk 50 to 100 mm ▲Jeonbuk 50 to 100 mm ▲Gwangju and Jeonnam 30 to 80 mm ▲Daegu, North Gyeongsang, and western inland of South Gyeongsang 30 to 80 mm ▲Busan, Ulsan, and South Gyeongsang (excluding western inland of South Gyeongsang), Ulleungdo, and Dokdo 20 to 60 mm ▲Jeju Island 20 to 80 mm, among others.

As it rains, the heat is expected to break. Temperatures nationwide will drop slightly, averaging around 26 degrees, which is lower than usual. The morning low is forecasted to be 20 to 25 degrees, while the daytime high is expected to be 23 to 30 degrees.

The morning low temperatures in major regions are expected to be 23 degrees in Seoul, 22 degrees in Incheon, 22 degrees in Chuncheon, 24 degrees in Gangneung, 23 degrees in Daejeon, 23 degrees in Daegu, 24 degrees in Jeonju, 23 degrees in Gwangju, 22 degrees in Busan, and 23 degrees in Jeju.

The daytime high temperatures will be 25 degrees in Seoul, 24 degrees in Incheon, 25 degrees in Chuncheon, 30 degrees in Gangneung, 27 degrees in Daejeon, 28 degrees in Daegu, 28 degrees in Jeonju, 27 degrees in Gwangju, 25 degrees in Busan, and 28 degrees in Jeju.

The fine dust concentration is expected to be at a "good" level across all regions.